The present invention relates in general to a bin vibrating discharge device for surge or blending bins or the like wherein an apron type conveyor formed of a series of chain supported slats or the like or a belt supported by a fixed bed conveys product to a discharge zone where vibration is imparted to the apron to effect gentle continuous discharge of material therefrom in a steady and even fashion.
Relatively slow moving conveyors are used in many industries handling a bulk product to blend their product or as a surge point to accommodate the fluctuations in production rates which occur upstream and downstream of the surge point.
These surge bins or blending bins are usually of large cross section in relation to the rate at which the stored product is discharged, so some means of producing an even discharge must be employed. Current practice uses rollers with readily projecting tines, chain supported or cam supported pin bars, and round or flat bars to dislodge a small quantity at a continuous or nearly continuous rate. Attempts have been made to vibrate the entire end of the storage bin by making the last few feet of the entire storage area of vibrating conveyor.
One of the common means of conveying the stored product to a discharge zone and discharging it is to provide an apron trained about rollers, with the bulk material arranged in a pile on the apron. If unsupported, the face of the pile of bulk material resting on the apron will slope downward at the discharge end at an angle equal to the angle of repose of the particular material. When the apron moves toward the discharge, the face of material moves with it and is relatively undisturbed by the slow motion of the apron. If the apron is of the chain supported slat type providing a series of transversely elongated slats defining the apron surface, when a slat after becoming tangent to the sprocket pitch line, or after a belt becomes tangent to the head roller if a sliding belt trained around rollers is used, the slat or belt surface assumes a rather sudden downward slope which causes a slice of material roughly the thickness of the slat to break away at one time and fall into the discharge. The material ceases to discharge until the next slat approaches the pitch line. The same action to a lesser degree is present with the belt apron and in both cases some means must be provided to cause the material to flow down the face of the pile in an even and continuous manner.
Most of the present devices used to control the bin discharge cause an agitation on the face of the pile by successively passing a pin or bar along and through the material in the face so that it rolls down the face and then in the take-away conveyor. Introduction of this foreign pin into the material causes breakage and results in additional reduction in material size which is undesirable. Introduction of a vibrating section above and at the discharge end of the apron results in a large unbalanced vibrating mass which is nearly impossible to isolate. Excess breakage more than the pinned discharge is caused by the transfer from the apron to vibrating section. The present invention is directed to an improved method of causing an even and continuous discharge of the surge bin or blending bin with reduced breakage of product by using a selective vibration device which can be adjusted for frequencies, position, preload and strength of vibration depending on the characteristics of the product stored. The present invention prevents the degradation produced by introducing a foreign object such as a tine or blade into the product. An object of the present invention, therefore, is the provision of an improved vibrating discharge structure for discharging a product from a surge bin or blending bin or the like in a manner causing an even and continuous discharge with reduced breakage of the product, wherein the vibration can be adjusted for frequencies, position, preload and strength of vibration depending on the characteristics of the product.
Another object of the present invention is the provision of a novel vibrating discharge structure for bins as defined in the immediately preceding paragraph, wherein a series of chain supported slats which either overlap or butt against one another provide the apron and vibration is imparted to individual slats as they approach the discharge zone at the discharge end of the apron to effect a gentle but continuous discharge of material from the face of the pile of material on the apron in a steady or even fashion. Alternatively, the apron may be similar to that described above but the slats are not close fitting and are covered by a light belt or membrane to prevent leakage, or the slat type apron may be displaced by an apron in the form of a belt supported by a packed bed over which the belt slides in the zone between rollers at opposite ends of the belt.
Other objects, advantages and capabilities of the present invention will become apparent from the following detailed description, taken in conjunction with the accompanying Figures illustrating a preferred embodiment of the invention.